The present invention relates to the field of communications systems, and, more particularly, to the field of fiber optic communications systems, such as installed along aerial routes, for example, and associated methods.
Some cable television systems in the past have used exclusively electrical coaxial cables to distribute TV signals from a headend to a plurality of individual subscribers. A main distribution coaxial cable extended along a route, and a series of taps were connected to the main distribution cable along the route. One or more coaxial drop cables extended outwardly from the taps to the individual subscribers.
Fiber optic cables are widely used for transmitting telecommunications signals over relatively long distances, and at higher data rates than electrical cables, such as coaxial cables. Fiber optic cables also offer immunity to lightning and other potential electrical faults along the route. A typical fiber optic cable includes a plurality of individual optical fibers contained within a protective sheath. Fiber optic cables are now commonly used in hybrid fiber/coax systems where the main, or trunk, cable is fiber/coax systems where the main, or trunk, cable is provided by an optical fiber cable.
Newer cable television systems are employing fiber optic cables throughout and are sometimes referred to as xe2x80x9cfiber-in-the-loopxe2x80x9d (FITL) systems. In other words, even the drop cables that extend to the individual subscribers are provided by optical fiber cables in an FITL system. Unfortunately, one drawback of a conventional FITL system is that the main distribution cable must be entered, the fibers accessed, spliced/interconnected and stored within a splice enclosure, and the entire assembly protected at each drop location along the route. This results in relatively high labor costs and material costs for the drop locations.
In addition, the splice enclosure is opened each time an additional subscriber is added to the system. This exposes the components to the risk of accidental damage.
U.S. Pat. No. 6,427,035 B1 to Mahony discloses a fiber optic network for connecting subscribers to a central office of the telephone service provider. The network includes a so-called xe2x80x9csplitter-terminal apparatusxe2x80x9d for connecting a plurality of drop cables to a secondary cable that, in turn, is connected to the primary cable. The splitter-terminal apparatus includes a housing, a splitter, and a plurality of connectorized terminations. Unfortunately, each tap is connected to the secondary cable at a conventional splice enclosure.
In view of the foregoing background, it is therefore an object of the present invention to provide a fiber optic communication system having a relatively low installation cost, a relatively low cost to add additional subscribers, and that reduces exposure of the distribution cable to damage.
These and other objects, features, and advantages of the present invention are provided by an aerial fiber optic cable system comprising a sub-distribution fiber optic system associated with the distribution fiber optic cable. More specifically, the aerial fiber optic cable system may comprise a distribution fiber optic cable extending along an aerial route, at least one fiber optic splice enclosure connected to the distribution fiber optic cable along the aerial route, and the sub-distribution fiber optic system extending along the aerial route in a direction away from the fiber optic splice enclosure.
The sub-distribution fiber optic system may comprise a plurality of spaced apart fiber optic taps along the aerial route, and a first sub-distribution fiber optic cable extending along the aerial route between the fiber optic splice enclosure and a first one of the plurality of fiber optic taps. The first sub-distribution fiber optic system may also comprise at least one second sub-distribution fiber optic cable extending along the aerial route between adjacent fiber optic taps so that the first sub-distribution fiber optic cable and the at least one second sub-distribution fiber optic cable are arranged in end-to-end relation. Drop fiber optic cables may extend away from the aerial route at each fiber optic tap.
Each of the sub-distribution fiber optic cables may comprise a desired length of cable and a fiber optic cable connector on at least one end thereof. Each fiber optic cable connector may comprise a factory installed fiber optic cable connector. In other words, pre-connectorized fiber optic cables may be used for the first and at least one second sub-distribution cables. Accordingly, the installation may be simplified and the cost reduced.
Each of the fiber optic taps may comprise a tap housing, and an input fiber optic connector carried by the tap housing for coupling to a preceding sub-distribution fiber optic cable. The fiber optic taps may also comprise an output fiber optic connector carried by the tap housing for coupling to a succeeding sub-distribution fiber optic cable, and a plurality of drop fiber optic connectors carried by the tap housing for coupling to respective drop fiber optic cables. The tap housing may also carry a fiber optic splitter, for example. The taps permit additional subscribers to be later added and without exposing the distribution cable to potential damage.
The aerial fiber optic cable system may further comprise a second sub-distribution fiber optic system extending along the aerial route in a second direction opposite the first direction. The first direction may be considered the forward direction, and the second direction a backward direction, for example. Accordingly, the fiber optic system may advantageously be extended over a greater range.
In accordance with another aspect of the invention, the aerial fiber optic cable system in some embodiments may include a lateral sub-distribution fiber optic system extending outwardly from the aerial route in a lateral direction away from the at least one splice enclosure. The lateral sub-distribution system may include a plurality of spaced apart fiber optic taps, with each tap comprising a tap housing and a plurality of tap fiber optic connectors carried thereby. The lateral sub-distribution system may also include a first lateral sub-distribution fiber optic cable extending between the at least one splice enclosure and a first one of the fiber optic taps, and at least one second lateral sub-distribution fiber optic cable extending between adjacent fiber optic taps. Accordingly, the first lateral sub-distribution fiber optic cable and the at least one second lateral sub-distribution fiber optic cable are arranged in end-to-end relation. In addition, the first lateral sub-distribution fiber optic cable and the at least one second lateral sub-distribution fiber optic cable may each comprise a pre-connectorized fiber optic cable.
The fiber optic cable system may also comprise a plurality of spaced apart vertical support structures, such as wooden utility poles, for example, defining the aerial route. A respective optical network unit may be connected to each drop fiber optic cable at the subscriber""s location.
A method aspect of the present invention is for installing an aerial fiber optic cable system. The method may comprise installing a fiber optic distribution cable along an aerial route, connecting at least one fiber optic splice enclosure to the fiber optic distribution cable along the aerial route, and installing a first fiber optic sub-distribution system extending along the aerial route in a first direction away from the at least one fiber optic splice enclosure.
Another method aspect of the present invention is also for installing an aerial fiber optic cable system, and may include installing a fiber optic distribution cable along an aerial route, and connecting at least one fiber optic splice enclosure to the fiber optic distribution cable along the aerial route. The method may also comprise installing a forward sub-distribution fiber optic system extending along the aerial route in a forward direction away from the at least one fiber optic splice enclosure, and installing a backward sub-distribution fiber optic system extending along the aerial route in a backward direction.
Yet another method aspect is also for installing an aerial fiber optic cable system. The method may include connecting at least one fiber optic splice enclosure to a fiber optic distribution cable along an aerial route, and installing a lateral fiber optic sub-distribution system extending outwardly from the aerial route in a lateral direction away from the at least one fiber optic splice enclosure.